Power hacksaw-machine.



A. RASMUSSEN.-

POWER HACKS/KW MACHINE. APPLICATION FILED MAR. 19. 1911.

a 0 U m m P d l UWIAMV dent of Racine Junction,

through the medium of a cable or actuated by the FTCEQ ANDREWBASMTTSSEN, OF BACINE JUNCTION,

Wisconsin.

rowan HAcKsAw-Miicnmn ineasaai.

Specification of Letters Patent.

Patented JanQi-dflltlild.

ori inal application'fiied February 14, 1am, se no. 79,1145. Divided-andthisaii udatiea'fiteaiirarbh is,

i917. 'Se ria1No.155', 7I1.

Tooll whom it may; comm "Be itknown that I, Axni'nw-Rasmossnn, acitizen'of the United States,- and a-resiin the county of Racine and State ofWisconsin, have invented certain "new and -usefullmprovemerits in PowerHacl;saw-l\lacliines; and do hereby declare that the followingis a full,clear, and exact description thereof, reference being had to theaccompanying drawings, and to the characters of reference markedthereon, which form .a part of this specification.

This invention relates to improvements in hack saws, and refers moreparticularly to an improved means to feed the saw blade toward the workduring the cutting stroke thereof and to release it from the workdur ingthe non-cutting stroke, so as to thereby avoid wear and to facilitatethe cooling of the saw blade during the non-cutting stroke.

My improvements are herein shown as applied to the type of hack sawillustrated in my application for U. S. Letters Patent, Serial No.781%8, filed February 1%, 1916, of which this application is a division.

The present improvements relate to a special form of dog and ratchetmechanism by which the feed movement of the saw is controlled, and inaccordance with the present invention the ratchet member has the form ofa disk having peripheral ratchet teeth and is connected to the saw guideframe like flexible connection that is wound about and attached to adrum which rotates with the ratchet member.

The figure of the drawing is apartial side elevation and partial sectionof a hack saw machine embodying my invention.

The frame of the saw consists ofa horizontal table 10 having suitablylocated openings therein for the passage of operative parts of themachine and which is supported on legs 11, 11. 12 designates avertically swinging saw frame guide andsupport that is pivotally mountedat its rear end on the main drive shaft 13 of the machineand supports atits forward end the usual sliding saw frame 1 between the legs of whichis stretched a hack saw blade 15.

The reciprocating saw frame l l is connected by a pitman 16 to asuitable'crank shaft 13, consisting in this instance of aneccentricallydisposed crank pin 17"of 'afcranledisk l 8 tliat is "fired tosaidrsha-ft-lii. Said shaft 13 is 'mounted i'n suitable bearings 20,which rise from the rear end of the table'10, and thesha-ft i's providedat one end with a belt pulley 21.

The weight'of'the saw frame and guide will be overbalancedaround'itspivot13 so as to tend to raise the sawframe 'and saw whenno feedpressureis exerted thereon, either by'means of a weight or spring. Asherein shown said over-balancing effect is produced by aspring 25whichsurrounds a rod 26 that is loosely connected atone end to a tailpiece 27 of the guide 12 and is provided atits other end with a shoulder28, between which and a downwardly facing surface on the frame 10 saidspring 25 is interposed. Said shoulder 28 constitutes part of, or isassociated with an adjusting nut which is screw threaded to the rod,whereby the overbalancing pressure of the spring 25 may be delicatelyadjusted. Obviously a weight suitably applied to the tail piece 27, inthe same general manner as shown in my aforesaid prior patent, mayeffect the same general result, but the spring is preferable, especiallyin the larger sizes of sawing machines.

The feed mechanism constituting the present invention is made as follows35 designates a disk which is mounted to rotate on shaft 36 which iscarried by depending brackets 37 of the machine frame. Rotatingwith'said disk and fixed thereto as herein shown is a drum 38, shown indotted lines, on which is adapted to be wound a cable 39 that isattached to the saw frame and supporting guide 12, the cable beingattached at its other end to the drum on which it is wound.

40 designates a feed dog which engages the teeth of said ratchet disk,and which is formed on the lower end of a'bar 41 that is looselyconnected or hinged at 12 to theforward end of a cam controlled feedlever 43. Said lever is pivoted at 44 to a standard 45, which rises fromthe base or bed plate 10 of themachine, The dog may be weighted so as tobe normally pressed toward the rotating disk but preferably a lightspring 48 is applied for this purpose. Said spring is shown'as' attachedat one end to thedog 40 and at its'other end'to the bracket 37. The rearend of the lever 43 carriesa bearing roller '50 which engages theperiphery of a cam 51 that is fixed to and rotates with the shaft 13, ormay be otherwise suitably driven therefrom. The periphery of the cam 31is divided into two equal parts, to wit :a higher part or track a and alower part or track I) connected by oblique or cam portions 0. 'Thebearing roller 50 carried by the rear end of the lever -13 is normallypressed toward or against the periphery of the cam 51 by meanspermitting said latter end of the lever to yield backwardly away fromthe cam. This may be effected either through the action of a spring orweight; a spring 53 being herein employed. The spring 53 surrounds a rod54: that is loosely connected at 55 to the lever 43 and said spring isinterposed between a shoulder 56 on said rod andone arm 58 of anL-shaped lever 59, that is perforated for the passage of said rod. 1Said rod is screw threaded to receive a nut 60 to prevent detachment ofthe rod from the lever. The lever is pivoted at 61 to the machine frameand a spring adjusting lever 62 fixed to lever 59, is carried to thefront end of the machine and is there provided with a suitable latch 63which cooperates with a locking bar 64. By this arrangement the feedmechanism may be adjusted to press the saw blade more or less lightlyagainst the work. When sawing relatively soft metals the pressure of thespring 53 may be so ad,- j usted as to press the bearing roller 50 ofthe lever 43 into contact with the lower track 5 of the cam 51 so as toobtain the maximum cut of the saw. The contact of the roller with thisportion of the cam limits the feed movement of the lever in eachoperation of the saw. l/Vhen cutting harder metals said spring will beadjusted to press-the saw more lightly against the work. When thebearing roller is engaged with the higher track a of the cam theforwardend of the lever 43 is raised to release the feed dog from the ratchetmember 35 and to permit the saw frame to be raised under the action ofspring 25.

perating in connection with the feed dog is a stop dog 66, which, asherein shown, engages the circular ratchet member on the sidethereof'remote from feed dog. .However, as in the construction describedin my aforesaid application, it is located adjacent to the feed dog.Said stop dog 66 is pivoted to a bracket 67 which depends from the bedplate 10 and is placed under the action of a spring 68 which is attachedat one end to the tail piece of the dog and is attached at its other endto a fixed member 69 which depends from said bed plate. 7 The functionof the stop dog is to limit the rising movement of the saw frameduringthe non-cutting stroke of the saw and at a time when the feed dogis released from the ratchet member so that when said feed dog is againdepressed through its feed stroke the teeth thereof engage the teeth ofthe ratchet member abovethose engaged in the earlier feed movements ofthe dog with the result of progressively feeding the saw to its work.This feed movement isa yieldingone due to the balancing of the feedoperations between the springs 25 and 53. When cutting hard materialthe'feed dog may not be raised at each release thereof from the ratchettooth last engagedto carry it into engagement with the next higherratchet tooth but may be operated through two more feed strokes on oneratchet tooth. However, the stop or check dog prevents the rising of thesaw under the action of spring 25 to such height as to cause the ratchettooth last engaged to pass under the dog, such as would occur if thestop dog were notipresent. The dog ishinged to the machine frame bymeans permitting slight lost motion, as by-. elongating the aperturethrough which the hinge pin for the dog extends. The risingof the sawblade from the bottom of the saw cut need not be great but onlysutficient to allow complete clearance of the saw blade teeth from thebottom of the saw cut. I have found inpractice that sixteen pitch teethon the ratchet is sutlicient to produce the desired clearance;

Both the feed and check or stop dogs may be simultaneously released inany suitable manner by some means equivalent to that shown in myaforesaid application.

The illustrated embodiment of my invention is'capable of some variationwithin the spirit and scope of the claims hereto appended and theinvention is not intended to be limited to the particular details shownexcept as the same are made subject to specific claims.

I claim as myinventioni- 1. Feed means for power hack saw machinescomprising, in combination with a reciprocating and raisable andlowerable saw frame and its saw, means acting on the frame tending tolift the saw-from its work during the non-cutting stroke and means tofeed the saw towardthe work during the cutting stroke comprising arotative circular ratchet member suitablyjconnected to the saw frame andfeed and stop dogs cooperating with said ratchet member.

2. Feed means for power hack saw machines comprising, in combinationwith a reciprocating and raisable and lower-able saw frame and its saw,means acting on the frame tending to lift the saw from its work duringthe non-cutting stroke and means to feed'the saw toward the work duringthe cutting stroke comprising a rotative circular ratchet membersuitably'connected to the saw frame, a feed dog acting on the ratchetmember, with cam meansfor controlling the same, and means to limit thelifting movement of the saw when the fed dog is released from theratchet member.

3. Feed means for power hack saw machines comprising, in combinationwith a reciprocating and raisable and lowerable saw frame and its saw,means acting on the frame tending to lift the saw from its work duringthe non-cutting stroke and means to feed the saw toward the work duringthe cutting stroke comprising a rotative circular ratchet membersuitably connected to the saw frame, a feed dog cooperating with saidratchet member, with resiliently applied cam controlled means to controlit and means for limiting the rising of the saw from the work when thefed dog is disengaged from the ratchet member.

4. Feed means for power hack saw machines comprising, in combinationwith a re ciprocating and raisable and lowerable saw frame and its saw,means acting on the frame tending to lift the saw from its work duringits non-cutting stroke, and means to feed the saw toward the work duringthe cutting stroke comprising a rotative circular ratchet membersuitably connected to the saw frame, a feed dog to engage said ratchetmember, a lever on which said feed dog is supported, with means forholding the dog yieldingly against the ratchet member, a cam forcontrolling said lever, a spring tend ing to force said lever towardsaid cam, and means to limit the rising of the saw from its work whenthe feel dog is operatively disengaged from the ratchet member.

5. Feed means for power hack saw machines comprising, in combinationwith a reciprocating and raisable and lowerable saw frame and its saw,means acting on the frame tending to lift the saw from its work duringits non-cutting stroke and means to feed the saw toward the work duringthe cutting stroke comprising a rotative circular ratchet membersuitably connected to the saw frame, a feed dog to engage said ratchetmember, a lever on which said feed dog is supported, a cam forcontrolling said lever, a spring tending to force the lever toward itscontrolling cam, means to vary the force of the spring acting on saidlever, and means to limit the rising of the saw from its work when thefed dog is operatively disengaged therefrom.

6. Feed mechanism for power hack saws comprising, in combination, a sawcarrying frame normally overbalanced away from the work, a rotativeratchet member, a drum turning with said ratchet member, a cable fixedto and wound on the drum and connected to said frame, a feed dogoperatively engaging said rotative ratchet member, with means forcontrolling the feed movement of the dog, and means to prevent reverserotation of the ratchet member when the feed dog is operativelydisengaged therefrom.

7. Feed mechanism for power hack saws comprising, in combination, a sawcarrying frame normally overbalanced away from the work, a rotativeratchet member, a drum turning with said ratchet member, a cable fixedto and wound on the drum and con nected to said frame, a feed dogoperatively engaging said rotative ratchet member, with means forcontrolling the feed movement of the dog, and a check dog cooperatingwith the ratchet member to prevent reverse rotation thereof when thefeed dog is operatively disengaged from the ratchet member.

In witness whereof I claim the foregoing as my invention, 1 hereinappend my signature in the presence of two witnesses at liacine,Wisconsin, this 27th day of February,

ANDREl/V HASMUSSEN, l/Vitnesses:

Trios. ALLEN, H. N. Bacon.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of ZEatents. Washington, D. (3.

